This paper acknowledges the difficulty of taking into account factors, such as thermal comfort in house design, as they can only be assessed in subjective terms. An attempt to solve these Problems was made as part of a field study of indigenous people in a tropical area - in this case the Solomon Islands. Subjects were asked to indicate how they felt on a graphic scale of thermal Sensation which was calibrated with the ASHRAE scale. These assessments were generally made in- doors. Thermal assessments were correlated with air temperature, the heat stress index, index of thermal stress, globe temperature and corrected effective temperature. Regression and probit analyses were applied to the results. It was found that air temperature provided a reasonable thermal index to measure the thermal neutrality of Solomon Islanders who were not involved in strenuous physical activity.